87991791925 has 6 divisors (see below), whose sum is σ = 109109822018. Its totient is φ = 70393433520.

The previous prime is 87991791907. The next prime is 87991791959. The reversal of 87991791925 is 52919719978.

It can be written as a sum of positive squares in 3 ways, for example, as 30316036 + 87961475889 = 5506^2 + 296583^2 .

It is not a de Polignac number, because 87991791925 - 2⁹ = 87991791413 is a prime.

It is a super-4 number, since 4×87991791925⁴ (a number of 45 digits) contains 4444 as substring.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1759835814 + ... + 1759835863.

Almost surely, 2^87991791925 is an apocalyptic number.

It is an amenable number.

87991791925 is a deficient number, since it is larger than the sum of its proper divisors (21118030093).

87991791925 is a wasteful number, since it uses less digits than its factorization.

87991791925 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3519671687 (or 3519671682 counting only the distinct ones).

The product of its digits is 25719120, while the sum is 67.

The spelling of 87991791925 in words is "eighty-seven billion, nine hundred ninety-one million, seven hundred ninety-one thousand, nine hundred twenty-five".